Push notification services are in widespread use for sending messages to various computing devices, including mobile devices. For example, a push notification may be sent from a message server to a user's mobile device to notify the user of receipt of a new email message. Push services can reduce the required work of a mobile device by relieving the mobile device of the need to check continuously for new email or other new messages from remote servers.
A downside of push messaging is that a mobile device must be awake, i.e., powered on, in order to receive new messages. Moreover, by delivering messages unprompted, a messaging server may repeatedly wake up a device, thus draining the device's battery power. Additionally, by sending messages to devices that are not in active use, messaging servers may overburden themselves unnecessarily. Accordingly, push messaging may still result in inefficient delivery of messages to a mobile device, particularly when the message server is unaware, or not up-to-date on the current status of the mobile device.